07/24/2014

Tiny Snail Plays a Big Role in Groundwater Conservation Efforts

Picture a snail that’s so tiny, it could disappear behind a kernel of corn.

Such small creatures can easily be overlooked-- but if you value having access to fresh, clean drinking water, then you should pay attention to this one.

Behold, the springsnail:

A live springsnail (Pyrgulopsis robusta) found in Snake River, Idaho. (Courtesy of Robert Hershler, Smithsonian Institution)

Springsnails belong to a group of invertebrates that grow to be less than 1/4 inch high, and are one of the most diverse types of aquatic animals native to North America. Scientists believe that these snails play an important role in freshwater ecosystems, keeping them clean by eating algae and serving as food for fish and other critters. More than 130 different kinds of springsnails live west of the Mississippi River alone, thriving in and around the same freshwater springs that humans depend on for drinking water, livestock grazing and recreation.

Over the past few decades, groundwater pumping and depletion in the western United States has greatly accelerated due to an increase in human demand and global climate change. The result: a large number of dried springs scattered throughout the West, water shortages for people living in these areas and major declines in springsnail populations. Scientists now consider the springsnail to be the poster child for imperiled ecosystems that are reliant on freshwater springs.

How does the fate of this snail affect you? To put it simply, save the springsnail and your groundwater is also saved.

A dried spring at Las Palomas, Mexico, formerly occupied by the now extinct Pyrgulopsis brandi, a species of springsnail. The spring dried out as a result of groundwater pumping. (Courtesy of James J. Landye)

The Smithsonian is playing a leading role in the fight to conserve the springsnail. A new study published online in Bioscience(July 16) by National Museum of Natural History scientist Robert Hershler reports that springsnails have become the focus of new conservation activities over the past few decades during which various species have started to disappear.

Most springsnail species have narrow ranges, often consisting of a single spring or system. If the spring dries up or becomes polluted from activities such as cattle grazing, these snails cannot survive. Invasive species in freshwater areas are also taking a toll on springsnail populations. At least five springsnail species have gone extinct since the early 1900s and 80% of living species are listed as endangered by the American Fisheries Society.

The good news is that during the past 25 years, considerable strides have been made in providing protection for springsnails and the fresh groundwater sources they call home. Scientists are beginning to understand how springsnail populations have changed over time, both from human activities, and, on longer time scales, from climate change. Museum collections provide important baselines for these studies-- the Smithsonian stewards over a million springsnail specimens that represent more than 100 different species collected since the 1980s.

While Hershler’s research is an important step towards better understanding these small snails, more foundational work needs to be done. His paper calls for additional research on the biology of the springsnail and links to a driving force behind conservation efforts in the western United States today—the need for fresh groundwater shared by humans and snails alike.

By Kathryn Sabella, Press Officer, Smithsonian's National Museum of Natural History